
body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    /* 渐变背景 - 您可以调整颜色以符合学校主题 */
    background: linear-gradient(135deg, #72edf2 10%, #5151e5 100%);
    overflow: hidden; /* 防止动画元素溢出时出现滚动条 */
}

.login-container {
    background-color: rgba(255, 255, 255, 0.9); /* 半透明白色背景 */
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 400px;
    text-align: center;
    /* 入场动画 */
    animation: fadeInScale 0.8s ease-out forwards;
}

@keyframes fadeInScale {
    0% {
        opacity: 0;
        transform: scale(0.9) translateY(20px);
    }
    100% {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.login-container h2 {
    margin-bottom: 30px;
    color: #333;
    font-size: 24px;
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: bold;
}

.form-group input[type="text"],
.form-group input[type="password"],
.form-group select {
    width: calc(100% - 20px); /* 减去padding */
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    box-sizing: border-box;
    transition: border-color 0.3s ease;
}

.form-group input[type="text"]:focus,
.form-group input[type="password"]:focus,
.form-group select:focus {
    border-color: #5151e5;
    outline: none;
}

.login-button {
    background-color: #5151e5;
    color: white;
    padding: 12px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    width: 100%;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.login-button:hover {
    background-color: #4141d5;
    transform: translateY(-2px); /* 轻微上移效果 */
}

.login-button:active {
    transform: translateY(0); /* 点击时恢复 */
}

.error-message {
    color: red;
    margin-top: 15px;
    font-size: 0.9em;
}

/* 简单的背景漂浮物动画 (可选) */
.floating-shapes {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    z-index: -1; /* 确保在登录框后面 */
}

.floating-shapes div {
    position: absolute;
    display: block;
    width: 20px;
    height: 20px;
    background: rgba(255, 255, 255, 0.2); /* 半透明白色形状 */
    bottom: -150px; /* 从底部开始 */
    animation: floatUp 25s infinite linear;
}

.floating-shapes div:nth-child(1) { left: 25%; width: 80px; height: 80px; animation-delay: 0s; }
.floating-shapes div:nth-child(2) { left: 10%; width: 20px; height: 20px; animation-delay: 2s; animation-duration: 12s; }
.floating-shapes div:nth-child(3) { left: 70%; width: 20px; height: 20px; animation-delay: 4s; }
.floating-shapes div:nth-child(4) { left: 40%; width: 60px; height: 60px; animation-delay: 0s; animation-duration: 18s; }
.floating-shapes div:nth-child(5) { left: 65%; width: 20px; height: 20px; animation-delay: 0s; }
.floating-shapes div:nth-child(6) { left: 75%; width: 110px; height: 110px; animation-delay: 3s; opacity: 0.1; }
.floating-shapes div:nth-child(7) { left: 35%; width: 150px; height: 150px; animation-delay: 7s; opacity: 0.05;}
.floating-shapes div:nth-child(8) { left: 50%; width: 25px; height: 25px; animation-delay: 15s; animation-duration: 45s; }
.floating-shapes div:nth-child(9) { left: 20%; width: 15px; height: 15px; animation-delay: 2s; animation-duration: 35s; }
.floating-shapes div:nth-child(10) { left: 85%; width: 150px; height: 150px; animation-delay: 0s; animation-duration: 11s; opacity: 0.08;}

@keyframes floatUp {
    0% {
        transform: translateY(0) rotate(0deg);
        opacity: 1;
        border-radius: 0;
    }
    100% {
        transform: translateY(-1000px) rotate(720deg);
        opacity: 0;
        border-radius: 50%;
    }
}
